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Plumbness of a chimney

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Mcgiiver
(@mcgiiver)
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This is a picture of the tallest chimney in America in 1888. It is at the Coats Thread Factory in East Newark NJ. As a child I grew up 2 blocks from there. I was poking around on line to see if the chimney and factory still exists, they do. Then I got wondering about the safety of the chimney. So my surveying question is, how do you accurately check the plumbness of?ÿ a tapered brick chimney 335 ft in height?
image
 
Posted : October 19, 2022 9:43 am
james-vianna
(@james-vianna)
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Shoot the perimeter of the base and compute a center. Then the same for the top via reflectorless

 
Posted : October 19, 2022 10:16 am
MightyMoe
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turn angles to the edge at the same height, split the two angles and shoot the outside at the mean of the two angles with a reflectorless, repeat at the top. Some calcs and the center of the two locations can be computed. If it doesn't calculate plumb repeat from a different location.?ÿ

 
Posted : October 19, 2022 10:52 am
rover83
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@james-vianna?ÿ

I agree, that's the easiest way.

?ÿ

If they were wanting to do a full safety check, though, not only check for center plumb, it only takes slightly more time to scan the sucker as it does to shoot the bottom and top.

 
Posted : October 19, 2022 11:11 am
leegreen
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Several terrestrial scans and control points with robot. Then cut 3d sections every 25ft or so.

 
Posted : October 19, 2022 11:23 am

bobwesterman
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Posted by: @mightymoe

turn angles to the edge at the same height, split the two angles and shoot the outside at the mean of the two angles with a reflectorless, repeat at the top. Some calcs and the center of the two locations can be computed. If it doesn't calculate plumb repeat from a different location.?ÿ

Seems to me it would be easier to drop a plumb line down the center and see how it looks at the bottom.

 
Posted : October 19, 2022 11:27 am
larry-scott
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@bobwesterman?ÿ

putting Simone at top with a plumb bob would be far more expensive time consuming and hazardous than theodolite measurements, combined with scanning.?ÿ

 
Posted : October 19, 2022 11:39 am
Larry Best
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Posted by: @larry-scott

@bobwesterman?ÿ

putting Simone at top with a plumb bob would be far more expensive time consuming and hazardous than theodolite measurements, combined with scanning.?ÿ

Why does Simone always get the cool jobs?

 
Posted : October 19, 2022 1:54 pm
Norman_Oklahoma
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Posted by: @james-vianna

Shoot the perimeter of the base and compute a center. Then the same for the top via reflectorless

?ÿ

I used just that technique to determine the plumb-ness of this water tower in 2012, the center of the 5 leg circles making data for the over all center at 4 different heights. It worked amazingly well.

image
 
Posted : October 19, 2022 2:29 pm
Williwaw
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From three radial directions +/- 60 degrees apart, using a theodolite to mean the angle from the two outside edges, first at the base, and then at the top from same set up. If all mean angles are equal, top and bottom from the three setups, itƒ??s plumb. If not, itƒ??s the leaning tower of Newark.

Just because I'm paranoid, doesn't mean they aren't out to get me.

 
Posted : October 19, 2022 2:34 pm

kscott
(@kscott)
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@williwaw?ÿ

This is how we monitored several stacks at a gas plant. The site was settling and the stacks were starting to lean. Complicating the survey was the safety measures required in the site; like gasmasks. Multiple angles were measured to the perimeter of each stack from 3 control points outside of the restricted site and the results were processed with StarNet. The StarNet settings were tweaked to draw error ellipses (circles) representing the section at the top and bottom of each stack. It made for very consise and easy to read reports. During our engagement the site settled up to a foot in some areas and the tallest tower was leaning about 3 feet out of plumb.

 
Posted : October 20, 2022 9:55 am